Oh Ye of little faith
I was just avoiding that whole issue, as I don't think the chain was the root issue. Otherwise you would see these motors overheating left and right as they chain stretched, which you don't see.
Doug
Anonther non-believer? Okay, that is fine, but let me just re-cap the situation for you:
Engine overheating, so the shop manual diagnostic steps were followed and each item according to the shop manual was checked and/or replaced and eliminated as a cause of the overheating.
New Moorcraft thermostat was installed when all new hoses were installed. The original hoses after 16 years and 235,000 miles were not leaking, but they were getting very soft.
Radiator was found to be leaking and it was replaced with a new one since the Mark VIII radiators cannot be repaired.
The heater core was checked for flow and it was flowing properly and was not leaking.
The cap on the water by pass tube was not holding pressure and it was replaced with a new one from Ford.
A new temp sensor wa installed.
The entire system was flushed and drained and the proper amount of water/coolant was installed. The system was properly burped and refilled. The cooling fan was coming on and was working properly
After all of the above was performed, the system did run cooler, but still was running hot and under load above 45 MPH would go into the red. So, if everything in the cooling system was either replaced, cleaned or filled and burped properly, why the oveheating problem?
In doing research about this problem, my good friend who helped me complete the timing chain job found an article that listed possible causes for overheating and stretched timing chains was on the list. The article had been based on the discovery of an engine that was also overheating and traced the cause to stretched timing chains.
My engine had been running poorly and we found oil in the sparkplug holes due to leaing valve covers. We had to remove them to replace the gaskets anyway, so we decided to remove the front cover to inspect the chains and tensioners.
We found that the tensioners were fully extended, but that the chains were still very loose. It was obvious that valve timing was off and not in phase with the ignition timing. The article described this as a possible cause of overheating.
We decided to replace all the chains and tensioners. Since the coils were covered in oil I decided to spring for a set of 8 accel coils and they were installed with new motorcraft plugs. After the timing chain job was complete, we restarted the engine and we were amazed at the difference in performance.
As I told you earlier, the car was tested under load at high speed and never once did the gauge go past the halfway mark. The engine is running as good as new and it is not overheating.
If stretched timing chains cannot cause overheating, why did replacing them all resolve the overheating problem?
Why didn't all the other fixes tried, fix the problem? So, please tell me why the engine was overheating before replacing all the chains?
Until you pull the cover and look at the tensioners, you will not be able to tell if the chains are stretched beyond the range of proper specifications.
